JPH0826926B2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field The present invention relates generally to continuously variable transmissions (CVTs). More specifically, it relates to a continuously variable transmission (hereinafter referred to as a transmission (CVT)) adapted for use in a small front-wheel drive vehicle. Transmissions (CVTs) have multiple drive ranges and synchronous switch points that switch from any drive range to another drive range.

PRIOR ART A typical vehicle transmission is discontinuously switched between a low speed, high torque range for starting the vehicle and a high speed, low torque range for operating the vehicle at highway speeds. In a manual transmission, shifting is accomplished by the engagement of gear sets. In automatic transmissions, shifting is accomplished by controlled engagement of friction elements. Such switching is stepwise approximate. Automotive engineers
It has long been recognized that efficiency would be improved if the transmission could be continuously stretched to compensate for changing loads, speeds, etc. This allows the engine to operate at maximum efficiency under changing conditions.

The transmission (CVT) has been known until now. A typical transmission (CVT) has a variable speed ratio with a pair of flanges attached to the drive shaft and a variable pulley that is movable with respect to the other flange so that one flange changes the pitch radius of the pulley. The drive mechanism (transmission) is used. Another similar variable pulley is mounted on the driven shaft. A suitable belt or chain connects the pulleys to transfer torque between the pulleys. When the pitch radius of one pulley is changed, the pitch radius of the other pulley is simultaneously changed in the opposite direction. As a result, the drive ratio between the drive shaft and the driven shaft is continuously and smoothly changed within the limit that limits the speed ratio range of the transmission. Although not required, this range is typically the overdrive ratio from the reduction ratio to the opposite.

In recent years, great efforts have been made to apply transmissions (CVTs) to automobile drivelines. An example of such a transmission (CVT) is US Pat. No. 2,933,952, US Pat.
There are 3,479,908 issues. Each of these patents has a split path transmission having a low speed range providing low speed, high torque drive in both forward and reverse directions, but having only a high gear ratio providing one low speed high torque drive in the forward direction. CVT) is shown. U.S. Pat. No. 3,340,749 shows a split path transmission (CVT) that provides multiple high ranges. However, this patent does not indicate a synchronous switching point at which the transmission is switched from one of the drive ranges to the other. Rather, the drive range should be continuously engaged to provide smooth power flow.

In transmission (CVT) technology, it is necessary to allow the driver of the vehicle to switch directly from one drive range to another. In particular, it is desirable for the driver to be able to choose between switching from a low speed range to a first high capacity range suitable for city driving or a second economical high speed range suitable for driving on highways.

(Problems to be Solved by the Invention) The present invention has been made in order to meet this need, and an object thereof is to combine a constant gear ratio drive mechanism, a pulley type transmission device and three clutch devices. To provide a continuously variable transmission having a first and a second high speed range for high speed drive.

(Means for Solving Problems) A first invention of the present application is a constant gear ratio deceleration drive having an input element, a drive element that is interlocked with the input element, and a driven element that is driven by the drive element. A mechanism, a transmission having a driving pulley that is interlocked with the input element and a driven pulley that is driven by the driving pulley, and meshes with a sun gear element, a ring gear element, a carrier element, and the sun gear element and the ring gear element. A continuously variable transmission having a planetary gear assembly having a plurality of planetary gear elements supported by the carrier element, and an output element, wherein the transmission is the driven pulley of the transmission. A first clutch device adapted to selectively engage with the sun gear element or the ring gear element; A second clutch adapted to selectively engage the driven element with the carrier element or the sun gear element, and to selectively engage the ring gear element or the carrier element with the output element The third gear ratio of the sun gear element to the tooth of the ring gear element is equal to the speed reduction ratio of the constant speed ratio reduction drive mechanism.

A second invention of the present application is rotatable on an input shaft, a driven shaft that is separated from the input shaft and is parallel to the input shaft, a drive element that is interlocked with the input shaft, and the driven shaft. A constant speed ratio deceleration drive mechanism that has a driven element that is supported by and that is driven by the drive element; a drive pulley that is interlocked with the input shaft; and a rotatably supported by the driven shaft and that is driven by the drive pulley. A planetary gear assembly having a transmission having a driven pulley to be driven, and a plurality of planetary gear elements supported by the carrier element and a sun gear element, a ring gear element, a carrier element and the sun gear element and the ring gear element. And a variable output continuously variable transmission having an output element, wherein the transmission causes the driven pulley of the transmission to move to the sun gear element. Is a first clutch device adapted to be selectively engaged with the ring gear element, and the driven element of the constant speed ratio reduction drive mechanism is selectively engaged with the carrier element or the sun gear element. A second clutch adapted to engage and a third clutch arrangement adapted to selectively engage the ring gear element or the carrier element with the output element, the sun relative to the teeth of the ring gear element. The ratio of the teeth of the gear element is equal to the reduction ratio of the constant speed ratio reduction drive mechanism, and the ring gear element, the carrier element and the output element are supported by the driven shaft and rotate with respect to the driven shaft. It is configured to be possible.

(Operation) In the above invention, the power from the input element or the input shaft is transmitted from the drive element of the constant gear ratio drive mechanism to the driven element. It is also transmitted from the drive pulley of the transmission to the driven pulley. Under these conditions, the first clutch engages the driven pulley with the sun gear element, the second clutch engages the driven sprocket with the carrier element, and the third clutch engages the ring gear element. When engaged with the output element, the output element is driven in the low speed range. The first clutch also engages the driven pulley with the ring gear element,
The output element is driven in the first high speed range when the second clutch engages the driven sprocket with the sun gear element and the third clutch engages the carrier element with the output element. Further, when the first clutch engages the driven pulley and the ring gear element, the second clutch is in the free position, and the third ring gear element engages the output element, the output element operates in the second high speed range. Driven.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

While the invention is conceivable in many different forms of embodiment, the preferred embodiment is shown and described in detail in the drawings. This disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to this example.

Referring to FIG. 1, a preferred embodiment of the present invention is a continuously variable transmission or transmission (CV) having a transmission housing 12.
T) is incorporated. The input element or drive shaft 14 is located on the first input or drive axis I in the housing
It is supported to rotate within 12. The drive shaft 14 receives power from an engine of an automobile (not shown) via a flywheel 16. The driven shaft 18 is supported on the second driven axis O so as to rotate in the housing.

The constant gear ratio drive mechanism 20 may be a chain drive train or other. The drive mechanism 20 comprises a drive element 22 in the form of a sprocket which is rotatable with an input shaft or drive shaft 14 on an axis I and a driven element in the form of a sprocket which is supported for rotation on a driven shaft 18 on an axis O.
24 and the chain 26 connecting the sprockets 22 and 24.
It has. As an example, the drive mechanism gives a reduction ratio of 0.5.

The transmission 28 comprises a variable drive pulley 30 which is rotatable with the drive shaft 14 on the axis I and a variable driven pulley 32 which is supported for rotation on the axis O with respect to the driven shaft 18. A suitable belt 34 or the like connects both pulleys 30 and 32. The pitch radii of the drive pulley 30 and driven pulley 32 are inversely varied so that the transmission provides a continuously variable drive ratio between predetermined limits. These limits are a drive ratio approximately equal to the drive ratio of the drive mechanism 20, a reduction ratio of 0.5 in this example, and an overdrive ratio of 2.0, which is the reciprocal.

The planetary gear assembly 36 includes a sun gear element or member 38 rotatable on the axis O with the driven shaft 18, a ring gear element or member 40 rotatable on the axis O with respect to the driven shaft 18, and on the axis O. It comprises a carrier element or member 42 rotatable with respect to the driven shaft 18 and a plurality of planetary gear elements or members 44 meshed with the sun gear element 38 and the ring gear element or member 40 and supported on the carrier member 42. In the preferred form of the invention, the ratio of the gears of the sun gear member to the number of teeth of the ring gear member is the drive mechanism 20.
Is almost numerically equal to the drive ratio of
Is.

In the preferred form of the invention, a friction clutch 46 is provided for engaging the driven pulley 32 and the first clutch A. Clutch A is, for example, a jaw clutch, which engages the toothed portion 50 of the driven shaft 18 from the free disengaged position shown in FIG. There is a toothed member 48 that can be switched to either of the two.

The driven sprocket 24 is interlocked with the second clutch B. The clutch B is, for example, a jaw clutch and engages the toothed portion 56 of the carrier member 42 from the free disengaged position shown in FIG. It comprises a toothed portion 54 which can be switched either to the right or to the left for engaging the toothed portion 58 of the driven shaft 18.

The output gear 60 and the like forming the output element are in driving relationship with the differential 62. The differential 62 is adapted to power the axles 64 and 66 of the vehicle to which it is attached.

The output gear 60 is linked with the third clutch C. Clutch C is, for example, a jaw clutch, which engages toothed portion 72 of ring gear member 40 from the free, disengaged position shown in FIG. 1 to the right or toothed portion of carrier member 42.
There is a toothed member 70 that can be switched to either the left side to engage 74.

The low speed range is established by switching clutches A, B and C to the right, as shown in FIGS. 1, 2 and 4a. Clutch A engages driven pulley 32 with driven shaft 18 and sun gear member 38, clutch B engages driven sprocket 24 with carrier member 42, and clutch C engages ring gear member 40 with output gear 60. To meet.

Under the above, the drive mechanism 20 provides a reduction ratio of 0.5 and the carrier member 42 rotates at 0.5 times the input speed. Transmission 2
Pulleys 30 and 32 so that 8 gives an overdrive ratio of 1.5
When the pitch radius is defined, the driven shaft 18 and the sun gear member 38 rotate at 1.5 times the input speed. As a result, the speeds of the ring gear member 40 and the output gear are zero. This is shown as the neutral point N in the graph of FIG. Since this is a gear neutral condition, it is desirable to disengage clutch 46 at this point to prevent vehicle creep.

As shown in FIG. 3, in the low speed range, the drive ratio of the transmission 28 is from the overdrive ratio 2.0 to the reduction ratio 0.5.
Can be changed in one direction. At an overdrive ratio of 2.0 to 1.5, the transmission (CVT) 10 drives in reverse with a gear ratio varying from -0.25 times the input speed to zero. From an overdrive ratio of 1.5 to a speed reduction ratio of 0.5, the transmission (CVT) 10 is driven forward at a speed ratio varying from zero to 0.5 times the input speed.

When the transmission gear ratio of the transmission 28 is 0.5, the transmission (CVT) 10 is at the synchronous switching point S. At this point, all elements on axis O rotate synchronously at 0.5 times the input speed. The transmission (CVT) 10 can be switched from any range to other ranges using a single jaw clutch or the like. No synchronizer is required.

As shown in FIGS. 1, 2, 3, and 4b, the transmission (CVT) 10 is a clutch at the synchronous switching point S.
The low speed can be switched to the first high speed range (high-1) by switching A, B and C respectively to the left. Clutch A engages driven pulley 32 with ring gear member 40, clutch B engages driven sprocket 24 with driven shaft 18 and sun gear member 38, and clutch C engages carrier member 42 with output gear 60. Engage. In the first high range, the transmission ratio of the transmission 28 can be changed in the opposite direction from a reduction ratio of 0.5 to an overdrive ratio of 2.0. Transmission (CVT) 10
Provides forward drive with a gear ratio that varies from 0.5 to 1.5 times the input speed.

As shown in FIGS. 1, 2, 3, and 4c, the transmission (CVT) 10 shifts the clutch A to the left and shifts the driven pulley 32 to the ring gear member 40 at the synchronous switching point S.
, The clutch B is switched to the free position to disengage the driven sprocket 24, and the clutch C is switched to the right to engage the ring gear member 40 with the output gear 60. Can be switched to. Second
In the high speed range, the gear ratio of the transmission can be changed in the opposite direction from a reduction ratio of 0.5 to an overdrive ratio of 2.0.

The first high speed range is suitable for driving in the city, while the second high speed range is suitable for driving on a highway. The transmission (CVT) 10 is intended to be switchable between a low speed range and a high speed range, but directly from one high speed range to the other high speed range if operating conditions require it. It can be switched.

In order to change the pitch radii of the drive pulley 30 and the driven pulley 32 in reverse so as to change the gear ratio range of the transmission 28 between the deceleration limit and the overdrive limit, the neutral position N
To engage or disengage the friction clutch 46 at and to switch the clutches A, B and C at the synchronous switching point S,
A suitable control device CS is provided.

Thus, the present invention contemplates a transmission (CVT) having multiple drive ranges. The transmission can be switched from any drive range to another drive range at the synchronous switching point. The low speed range provides low speed, high torque drive on either side of the neutral position. In the low speed range, the transmission (CVT) has a slit path configuration. That is, the torque is distributed through both the constant speed ratio drive mechanism and the transmission. The first high speed range provides high speed, low torque drive. In this range, the transmission (CVT) has a slit path configuration. Second
The high speed range provides a high speed, low torque drive but has a higher maximum overdrive gear ratio than the first high speed range. In this range, the transmission is a single pass
path) form. The constant speed ratio drive mechanism is released,
All torque is distributed via the transmission.

The values for the various gear ratios are given as examples. The designer is free to choose other values to meet the particular requirements.

(Effect) According to the present invention, since the first and second high speed ranges are provided in high speed driving, the vehicle can be driven more efficiently and smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view of the continuously variable transmission of the present invention showing elements of the continuously variable transmission at the synchronous switching point where the clutch is released, and FIG. 2 shows the position of the clutch of the continuously variable transmission. FIG. 3 is a simplified graph showing the relationship between the speed ratio of the transmission and the speed ratio of the transmission in each drive range, and FIG. 4a is a schematic diagram showing the continuously variable transmission in the low speed range. 4b is a schematic diagram showing the continuously variable transmission in the first high speed range, and FIG. 4c is a schematic diagram showing the continuously variable transmission in the second high speed range. 10: continuously variable transmission 14: input means (driving shaft), 18: driven shaft 20: constant gear ratio drive mechanism, 22: drive element 24: driven element, 28: transmission device 30: drive pulley, 32: driven gear Drive pulley 34: chain, 36: planetary gear assembly 38: sun gear member, 40: ring gear member 42: carrier member, 44: planetary gear member 60: output element (output gear) A, B, C: clutch

Claims (6)

[Claims] 1. A constant gear ratio deceleration drive mechanism having an input element (14), a drive element interlocking with the input element and a driven element driven by the drive element, and interlocking with the input element. A transmission (28) having a driving pulley (30) and a driven pulley (32) driven by the driving pulley, a sun gear element (38), and a ring gear element (4).
0), a carrier element (42) and a planetary gear assembly (36) having a plurality of planetary gear elements (44) meshed with the sun gear element and the ring gear element and supported by the carrier element, and an output element (60). In the continuously variable transmission (10) for synchronous switching, the transmission uses the driven pulley of the transmission (28) as the sun gear element (38) or the ring gear element (4).
0) and a first clutch device (A) adapted to selectively engage with the carrier element (42) or the sun gear element. Second clutch (B) adapted to be selectively engaged, and a third clutch adapted to selectively engage the ring gear element or the carrier element (42) with the output element (60). And a clutch device (C), wherein the ratio of the teeth of the sun gear element to the teeth of the ring gear element is equal to the reduction ratio of the constant speed ratio reduction drive mechanism. 2. The continuously variable transmission according to claim 1, further comprising another clutch device (46) for releasing the driven pulley of the transmission from the sun gear element and the ring gear element. transmission. 3. The continuously variable transmission according to claim 2, wherein the another clutch device (46) causes the driven pulley of the transmission to move when the transmission ratio of the transmission is equal to the reduction ratio. A continuously variable transmission comprising a friction clutch device for releasing from the sun gear element and the ring gear element. 4. An input shaft (14), a driven shaft that is separated from the input shaft and is parallel to the input shaft, a drive element that is interlocked with the input shaft, and a driven shaft that is rotatable. A constant speed ratio deceleration drive mechanism having a driven element that is supported by and driven by the drive element, a drive pulley (30) that is interlocked with the input shaft, and rotatably supported by the driven shaft and A transmission (28) having a driven pulley (32) driven by a driving pulley, and a sun gear element (38), a ring gear element (40), a carrier element (42), and the sun gear element and the ring gear element. A continuously variable transmission (10) for synchronous switching, comprising a planetary gear assembly (36) having a plurality of planetary gear elements (44) supported by the carrier element, and an output element (60), transmission The said driven pulley sun gear element (38) or the ring gear element of the transmission (28) (4
0) and a first clutch device (A) adapted to selectively engage with the carrier element (42) or the sun gear element. Second clutch (B) adapted to be selectively engaged, and a third clutch adapted to selectively engage the ring gear element or the carrier element (42) with the output element (60). And a ratio of the teeth of the sun gear element to the teeth of the ring gear element is equal to the reduction ratio of the constant speed ratio reduction drive mechanism, the ring gear element, the carrier element, and the output. Continuously variable transmission, characterized in that the element is supported by the driven shaft and is rotatable with respect to the driven shaft. 5. The continuously variable transmission according to claim 4, further comprising another clutch device (46) for releasing the driven pulley of the transmission from the sun gear element and the ring gear element. transmission. 6. The continuously variable transmission according to claim 5, wherein the another clutch device (46) causes the driven pulley of the transmission to move when the transmission ratio of the transmission is equal to the reduction ratio. A continuously variable transmission comprising a friction clutch device for releasing from the sun gear element and the ring gear element.